<?php
/*****************
substr_text()函数
字符串截取(中文字无乱码)
$str      字符串
$start    起始位置，默认为0
$length   截取长度
$charset  编码
$suffix   省略符号
*****************/
function substr_text($str, $start=0, $length, $charset="utf-8", $suffix="")
{
	if(function_exists("mb_substr")){
		return mb_substr($str, $start, $length, $charset).$suffix;
	}elseif(function_exists('iconv_substr')){
		return iconv_substr($str,$start,$length,$charset).$suffix;
	}
	$re['utf-8']  = "/[\x01-\x7f]|[\xc2-\xdf][\x80-\xbf]|[\xe0-\xef][\x80-\xbf]{2}|[\xf0-\xff][\x80-\xbf]{3}/";
	$re['gb2312'] = "/[\x01-\x7f]|[\xb0-\xf7][\xa0-\xfe]/";
	$re['gbk']    = "/[\x01-\x7f]|[\x81-\xfe][\x40-\xfe]/";
	$re['big5']   = "/[\x01-\x7f]|[\x81-\xfe]([\x40-\x7e]|\xa1-\xfe])/";
	preg_match_all($re[$charset], $str, $match);
	$slice = join("",array_slice($match[0], $start, $length));
	return $slice.$suffix;
}


/************
getIp()  获取用户真实IP 
************/
function getIp() { 
     if (getenv("HTTP_CLIENT_IP") && strcasecmp(getenv("HTTP_CLIENT_IP"), "unknown")) 
         $ip = getenv("HTTP_CLIENT_IP"); 
     elseif (getenv("HTTP_X_FORWARDED_FOR") && strcasecmp(getenv("HTTP_X_FORWARDED_FOR"), "unknown")) 
         $ip = getenv("HTTP_X_FORWARDED_FOR"); 
     elseif (getenv("REMOTE_ADDR") && strcasecmp(getenv("REMOTE_ADDR"), "unknown")) 
         $ip = getenv("REMOTE_ADDR"); 
     elseif (isset ($_SERVER['REMOTE_ADDR']) && $_SERVER['REMOTE_ADDR'] && strcasecmp($_SERVER['REMOTE_ADDR'], "unknown")) 
         $ip = $_SERVER['REMOTE_ADDR']; 
     else 
         $ip = "unknown"; 
     return ($ip);
}


?>